(1) Field of the Invention
The invention relates to the formation of a connection structure forming the physical and electrical connection between an integrated circuit element and a substrate. The connection structure is formed using composite bumps having a polymer body covered by a conductive metal coating and conductive particles suspended in a non-conductive binder.
(2) Description of the Related Art
The related Patent Applications, listed above, discuss composite bumps and bonded structures using composite bumps. U.S. Pat. No. 4,936,002 to Tagusa et al discusses bonding one or more conductive particles to a single connection. A Japanese article "Next Generation Liquid Crystal Display and High Density Package Technology," Finetech Japan '94 Conference Proceeding, Jul. 13, 1994 discusses the use of an anisotropic conductive film to form interconnections. U.S. Pat. No. 4,731,282 to Tsukagoshi et al discusses the use of an anisotropic conductive film.
This invention overcomes the disadvantage of other methods of using conductive films in forming interconnections by combining conductive films formed from conductive particles suspended in a non-conductive binder with the composite bump. The relatively low Young's Modulus of the composite bump allows the interconnections to be formed with substantially reduced recoil forces. These reduced recoil forces allow the interconnection to be formed with substantially reduced bonding forces and with less tendency to open the connection after it has been formed.